Stable effervescent composition



Patented June 1 7, 1930 UNITED STATES PATENT OFFICE LIONEL r. ANDREWS, or NORTH JAMAICA, NEW YORK, AssisNoR 'ro E. a. saunas a $0118, or NEW YORK, N. Y., A CORPORATION or NEW YORK STABLE EFFERVESCENT COMPOSITION No Drawing.

My invention relates to effervescent mixtures, particularly those for medicinal purposes, and to substances to be used as constituents thereof. I

5 Efiervescent mixtures as heretofore prepared, usually containing citric acid as their acidic ingredient, have been unstable, especially when subjected to high temperatures or considerable humidity, such as are encountered in various regions and during the summer and rainy seasons. 1n these circumstances, the components of the mixture interact prematurely and the preparation loses a large portion of its effervescent power in a relatively short time, the liberation of gases frequently being so great as to eject the stopper from the container. If exposed to the atmosphere for a period of about two days, these preparations generally become incapable of further efi'ervescence.

It has been attempted to substitute tartaric acid for citric in order to overcome these disadvantages, but tartaric acid is open to the objection that it reacts with any potassium compounds that may be present to form the comparatively insoluble salt potassium bitartrate, whereas ra id solubility is essential to the eflicacy o eflervescent preparations.

It is an object of my invention to provide for efiervescent compositions an ingredient that shall render them stable under ordinary conditions and even when unusual temperatures and humidities prevail.

I have found that soluble acid citrates. particularly mono-alkali-metal dihydrogen citrates, are well suited to re lace citric acid as the acidic ingredient of e ervescent preparations, being undecomposable by temperatures as high as 120 C. In admixture with an alkali-metal bicarbonate, such salts may be exposed to air for indefimte periods withoutacting on the said bicarbonate; and the active. life of the preparation under the various conditions of storage and use is thereby very much prolonged. In fact, I now have samples that have already lain open to the action of the atmosphere for about five months without sufiermg any diminution in Application filed April 12, 1928. Serial No. 269,618.

citrates, when acted upon by potassium compounds, form salts readily soluble in water.

In preparing effervescent compositions in accordance with my invention, I follow the customary procedures for like compositions of the prior art except that I substitute for the citric. acid in the latter a slightly greater, say by about 15%, proportion of my acid citrates. For example, in making efiervescent triple bromide tablets I merely intermingle the following ingredients in the relative proportions specified and compress the mixture: monosodium dihydrogen citrate 240, sodium bicarbonate 127, sodium bromide 58, potassium bromide 58,'ammonium bromide 29.

By the term alkali metal as used herein I mean to include not only the membersv ofthe alkali group but also ammonium.

It will be understood that the specific processes and substances given herein are merely illustrative of the practice of my invention and that various changes may be made within the scope of the accompanying claims without departing from the invention or sacrificing any of the advantages thereof.

I claim:

1. An effervescent composition containing a mono-alkali-metal dihydrogen citrate.

4. An effervescent composition containing monosodium dlhydrogen citrate.

5. As an acidic ingredient of effervescent composltlons monosodium dlhydrogen citrate.

In testimony whereof I aflix my signature.

LIONEL T. ANDREWS.

efiervesc ibility. Furthermore, such acid 

